rails - application.css asset not found in production mode

Question

I'm upgrading an application to use the asset pipeline.

I've got the css assets compiling into an application css file but they not being found when I run the application in production mode with

RAILS_ENV=production bundle exec rails s

and I visit any page I get the correct output from the database but no styling and the log shows:

ActionController::RoutingError (No route matches [GET] 
"/assets/default.scss-1a27c...f07c.css"):

Even though that file exists in public/assets

$ ls public/assets/def*
public/assets/default.scss-1a27c...f07c.css     public/assets/default.scss.css
public/assets/default.scss-1a27c...f07c.css.gz  public/assets/default.scss.css.gz

What do I need to change to get the server to find the asset file?

Same is happening for my other .css files. They get compiled into public/assets with finger prints but then are not found.

Page source is showing:

<link href="/assets/default.scss-1a27c...f07c.css" 
media="screen" rel="stylesheet" type="text/css" />

The rails (haml) source is = stylesheet_link_tag 'default.scss.css'

public.assets curently includes has the following files.

$ ls public/assets/def*
public/assets/default.scss-1a27c22229b7b522066181f27af4f07c.css
public/assets/default.scss-1a27c22229b7b522066181f27af4f07c.css.gz
public/assets/default.scss.css
public/assets/default.scss.css.gz

application.rb has

$ cat config/application.rb 
require File.expand_path('../boot', __FILE__)

# Pick the frameworks you want:
require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "sprockets/railtie"
# require "rails/test_unit/railtie"

if defined?(Bundler)
  # If you precompile assets before deploying to production, use this line
  Bundler.require(*Rails.groups(:assets => %w(development test)))
  # If you want your assets lazily compiled in production, use this line
  # Bundler.require(:default, :assets, Rails.env)
end

module Linker
  class Application < Rails::Application
    config.encoding = "utf-8"
    config.filter_parameters += [:password]
    config.assets.enabled = true
    config.assets.initialize_on_precompile = false # For Heroku
    config.assets.version = '1.0'
  end
end

config/environments/production has:

$ cat config/environments/production.rb 
Linker::Application.configure do
  config.consider_all_requests_local       = false
  config.action_controller.perform_caching = true
  config.assets.precompile += ['default.scss.css','main.css', 'jquery-ui-1.8.22.custom.css']
  config.serve_static_assets = false
  config.assets.compress = true
  config.assets.compile = false
  config.assets.digest = true
  config.log_level = :debug
  config.i18n.fallbacks = true
  config.active_support.deprecation = :notify
end

This seems to be happening for all assets, e.g.

Started GET "/assets/default.scss-1a27c22229b7b522066181f27af4f07c.css" for 127.0.0.1 at 2014-02-23 10:24:47 -0500
ActionController::RoutingError (No route matches [GET] "/assets/default.scss-1a27c22229b7b522066181f27af4f07c.css"):
Started GET "/assets/main-6864687b4114a1c316e444bd90f233ff.css" for 127.0.0.1 at 2014-02-23 10:24:47 -0500
ActionController::RoutingError (No route matches [GET] "/assets/main-6864687b4114a1c316e444bd90f233ff.css"):
Started GET "/assets/jquery-ui-1.8.22.custom-24319b4b1218846a3fe22a0479ae98b4.css" for 127.0.0.1 at 2014-02-23 10:24:47 -0500
ActionController::RoutingError (No route matches [GET] "/assets/jquery-ui-1.8.22.custom-24319b4b1218846a3fe22a0479ae98b4.css"):
Started GET "/assets/application-fc1d492d730f2a45581a40eac4607db8.js" for 127.0.0.1 at 2014-02-23 10:24:47 -0500
ActionController::RoutingError (No route matches [GET] "/assets/application-fc1d492d730f2a45581a40eac4607db8.js"):
Started GET "/images/link.ico" for 127.0.0.1 at 2014-02-23 10:24:48 -0500
ActionController::RoutingError (No route matches [GET] "/images/link.ico"):

Answer 1

Rails by default doesn't serve assets under public. See your production.rb:

  config.serve_static_assets = true

Change that to true and you're good to go. (Note: you don't want that to be true in production, remember to change it back before deploying!)

See Configuring Rails Applications for details.

In rails 6, in the default production.rb there should be a line

config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?

So run your server with

RAILS_SERVE_STATIC_FILES=true rails server -e production

or set config.public_file_server.enabled=true in production.rb. See answers below for rails 4 and 5.